Method and device for decontaminating water which contains metal and/or is radioactively contaminated

Abstract

The invention relates to an efficient process and device for the decontamination of waters polluted with heavy metals, semimetals and/or radionuclides by cation exchange and electrochemical deposition of the anions.

1. A process for the decontamination of metal-bearing and/or radioactively polluted waters containing heavy metals, semimetals and/or radionuclides in cationic and anionic forms, wherein
 following removal of insoluble components possibly present, the metals and/or radionuclides present in cationic form are adsorbed on a cation exchanger, and the metals and/or radionuclides present in anionic form are removed as neutral elements by electrochemical deposition, each of these two steps being carried out at least once, and the order of these, steps being interchangeable. 
 
     
     
       2. The process according to  claim 1 , wherein
 a bioadsorber, preferably a phosphorylated bioadsorber is used as cation exchanger. 
 
     
     
       3. The process according to  claim 1 , wherein
 the pH of the waters is adjusted to values of from 4 to 10, preferably from 5 to 7, prior to eliminating the metals and/or radionuclides present in cationic form. 
 
     
     
       4. The process according to  claim 1 , wherein
 either a base metal having a more negative normal potential than the metals/radionuclides to be deposited or a contact element is used in the electrochemical deposition of the metals and/or radionuclides present in anionic form, said contact element consisting of a noble metal serving as cathode and a less noble metal serving as anode. 
 
     
     
       5. The process according to  claim 1 , wherein
 prior to eliminating the metals and/or radionuclides present in anionic form, the pH of the water is adjusted to a value of from 1 to 6, preferably from 1.5 to 3. 
 
     
     
       6. A process for the decontamination of metal-bearing and/or radioactively polluted waters containing heavy metals, semimetals and/or radionuclides in anionic form, wherein
 the metals and/or radionuclides present in anionic form are removed as neutral elements by electrochemical deposition. 
 
     
     
       7. The process according to  claim 6 , wherein
 either a base metal having a more negative normal potential than the metals/radionuclides to be deposited or a contact element is used in the electrochemical deposition of the metals and/or radionuclides present in anionic form, said contact element consisting of a noble metal serving as cathode and a less noble metal serving as anode. 
 
     
     
       8. The process according to  claim 6 , wherein
 prior to eliminating the metals and/or radionuclides present in anionic form, the pH of the water is adjusted to a value of from 1 to 6, preferably from 1.5 to 3.